1. Technical Field
This invention relates to printers for printing on media such as labels and, more particularly, to a printer for printing on a printing face of a strip media having adhesive on a back face opposite the printing face comprising, a moving surface of a release material which does not bond to the adhesive extending linearly between an entrance and an exit of a print zone to provide a temporary liner supporting strip media within the print zone; means for moving strip media through the print zone in combination with the temporary liner; a printhead located within the print zone for printing on strip media within the print zone; and, means for non-contactingly releasing strip media emerging from the print zone from the temporary liner.
2. Background Art
Methods and apparatus for printing strip, roll-fed, media such as labels are well known in the art. Where there is no adhesive backing or the adhesive backing is temporarily covered with a removable liner material, the printer 10 can be configured as in FIG. 1. The printer 10 has a supply roll 12 of media 14, a fixed platen 16, and a printhead 18 positioned over the platen 16. The media 14 passes between the platen 16 and the printhead 18 and is pulled through by a pair of drive rollers 20. If the print surface of the media 14 is thermally activated, only a thermal printhead 18 is required. If the print surface of the media 14 is printed by thermal transfer or impact printing, an ink ribbon 22 from a supply roll 24 to a take-up roll 26 is also required in addition to the appropriate printhead 18. Where used, the ribbon 22 passes between the printhead 18 and the print surface of the media 14.
More recently, for various reasons of no importance to this application, so-called "linerless" media has gained great popularity. The linerless media has adhesive backing but no easily removable liner over it. Thus, it is susceptible to sticking to surfaces within a printer in which it is used. If the fixed platen 16 of FIG. 1 is employed, the results can be as in FIG. 2 where the adhesive on the media 14' has adhered to the surface of the platen 16 and the media 14' has been broken from the pulling force of the drive rollers 20. The loose end of the media 14' has also wound itself around the bottom drive roller 20 by adhering thereto and any inertia of the supply roll 12 has caused the media 14' to bunch up against the platen 16 and printhead 18. All in all, to try that approach could result in possible disaster for the user.
As another approach, the prior art has suggested employing a platen roller 25 of sufficient diameter to support the media 14' under the printhead 18 as depicted in FIG. 3. This suggested approach is also fraught with possible problems as depicted in the figure. Like the approach of FIG. 2, the media 14' may wind itself around the bottom drive roller 20 by adhering thereto. It may also adhere to the platen roller 25 until pulled off by the drive rollers 20 or adhere more fully to the platen roller 25 and pull the media 14' back through the drive rollers 20 or break it. To prevent such a happening, it has been suggested to put little fingers in strategic locations to pick the media 14' free from the platen roller 25 should it become attached to the surface thereof. All in all, another approach that could result in problems of disastrous results for the user and an overly complex design.
In European Patent Application 0 577 241 A2 of Thomas P. Nash as assigned to Moore Business Forms, Inc. which claims priority of U.S. application Ser. No. 907,511 filed Jan. 7, 1992 and which European Patent Application was published on May 5, 1994 in Bulletin 94/01 there is a printing apparatus which non-contactingly prints on pre-cut labels having a linerless adhesive employing an ink-jet type of printer. FIG. 4 depicts the apparatus and, in general, is the same as FIG. 1 of that application. The linerless media 50 has a printing surface 52 and an adhesive surface 54. The media 50 comes off the roll through rollers 56 and 58 which drive the media 50 to a cutting station 60, The cutting station 60 cuts the media 50 into labels 62 which are held onto the surface of the large roller 64 by atmospheric pressure as a result of a vacuum maintained within the roller 64. The printing surface 52 is adjacent the surface of the roller 64 and the adhesive surface 54 faces outward. The labels 62 are delivered by the roller 64 onto a transport system 66 which comprises a plurality of spaced tube belts 68 which rotate longitudinally in the direction of the arrows. There is also a vacuum chamber 70 under the belts 68. Thus, the labels 62 are deposited onto the belts 68 with the adhesive surface 54 contacting the belts 68. Since there is so little contact area between the adhesive surface 54 and the circular cross-section tube belts 68, it is necessary to have the vacuum chamber 70 which sucks between the belts 68 thereby causing atmospheric pressure to hold the labels on the belts 68.
As the labels 62 move along the belts 68, the release-coated printing surface 52 is heated by a hot platen 72 so that the ink will stick to the printing surface 52. After the platen 72 has heated the printing surface 52, a hot-melt wax ink-jet printer 74 sprays the "printing" onto the labels 72. At the end of the belts 68, there are a plurality of rollers 76 disposed between the spaced tube belts 68. The rollers 76 have an outside diameter which is greater than the thickness of the tube belts 68. Thus, the rollers 76 push the labels 72 up and off of the belts 68; and, in cooperation with opposing pinch rollers 78, push the printed labels 72 onto the surface of a product, such as envelopes 80, which are moved along the path 82 by the transport system 84.
As can be appreciated, the above-described apparatus is costly, bulky, and complicated. It certainly is not adapted to printing linerless labels in a portable and lightweight manner. The vacuum supply alone negates any possibility of using such technology in a portable lightweight printer. The requirement that the printhead be non-contacting so that ink-jet printing requiring pre-heating of the release coating on the printing surface is also self-defeating to the idea of a small, inexpensive, and lightweight portable printer for linerless media.
Wherefore, it is an object of the present invention to provide a drive and support mechanism and method for linerless media when printing thereupon by any approach using a printhead requiring support of the media in the print zone.
It is another object of the present invention to provide a drive mechanism and method for linerless media when printing thereupon by any approach using a printhead in which the media cannot adhesively seize and be broken.
It is still another object of the present invention to provide a drive and support mechanism and method for linerless media when printing thereupon by any approach using a printhead which is simple in design and construction.
It is yet another object of the present invention to provide a drive and support mechanism and method for linerless media which does not require a vacuum supply.
Other objects and benefits of this invention will become apparent from the description which follows hereinafter when read in conjunction with the drawing figures which accompany it.